Janus and Prometheus - Saturn's Moons Slideshow

Here are Janus and Prometheus, two moons that orbit Saturn along the S-ring. Janus is just a bit larger than Epimetheus that you just saw in the previous slide. While the two moons may look close to each other, they are actually about 160,000 kilometers from each other. Janus is about 180 kilometers across while Prometheus is about 100 kilometers across. You may notice that these moons look like small asteroids. Some astronomers believe that many of Saturn's moons are asteroids that are trapped in the gas giant's gravity.

Janus is the moon just below the rings and Prometheus can be seen to be a little more stretched out than Janus. Prometheus is one of the shepherd moons (with Pandora) that keeps Saturn's rings well defined. The Cassini spacecraft will place itself in many positions where it can photograph multiple moons in the same image. We are slowly realizing the effect all of the Saturnian moons have on the shape of Saturn's rings.